Door lock mechanism

ABSTRACT

A door lock mechanism, characterized by that a rotatable disk latch having a plurality of recesses each adapted for engagement with a striker when a door fitted with the door lock mechanism less the striker is provided, and a rotatable pawl is provided in close proximity, said pawl being adapted for mechanical cooperation with said recesses or notches successively.

11 1 1111 3,899,416 Kazoaka 1 May 7, 1974 1 DOOR LOCK MECHANISM 3,415,559 12/1968 Jeavons 11 292/216 920,444 5/1909 Essi 292/50 [75] Inventor: Kemch' Kamaka Japan 3,201,163 8/1965 Pick les 292/216 [73] Assignee: Aisin Seiki Company Limited, 3,381,993 5/1968 Arlauskas 292/216 Kariya-shi, Japan Primary Examiner-Richard E. Moore [22] Flled' 1972 Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, [21] Appl. N0.: 218,439 Zinn & Macpeak Related US. Application Data [62] Division ofSer. N0, 4,370,.lan. 20, 1970, abandoned. [57] ABSTRACT 521 US. Cl. 292/216 A door lock mechanism Characterized by that a 51 int. 19056306 able disk latch having a plurality of recesses each [58] Field of Search 292/198 216 280 DIG 26 adapted for engagement with a striker when a door fit 292/DIG ted with the door lock mechanism less the striker is provided, and a rotatable pawl is provided in close [56] References Cited proximity, said pawl being adapted for mechanical co- UNITED STATES PATENTS operation with said recesses or notches successively. 3,190,682 6/1965 Fox et al 292/216 3 Claims, 7 Drawing Figures PATENTEWAY 1:914

SHEET 1 BF 2 FIG.

11 noon LOCK MECHANISM This application is a continuation of application Ser. No. 4,370 filed Jan. 20, 1970 and now abandoned.

This invention relates to improvements in door lock mechanisms, especially those for use in automotive vehicles.

With the recent tendency of accelerated speed-up of the automotive vehicle speed, it is highly desirous to prevent a sudden and unintentional opening of the vehicle door on an emergency stop of the running automotive at a high speed, so as to prevent the riding person or persons from being thrown out of the vehicle through the flown open door. As a counter and safety measure against such kinds of accidents, it has already been proposed to substantially intensify the structure of the door lock mechanism, especially for increasing the breaking strength of the mechanism. In this respect, the disk latch member has been employed and arranged to be rotatable in a circular recess formed on a mounting member made integral with the base element of the door lock, a U- or similar shaped striker being used for cooperation with the disk latch. In this way, substantial success has been attained in the increase of the breaking strength of the latch per se, as well as the mounting member thereof.

It is an object of the present invention to provide a door lock mechanism, capable of performing an effective non-opening function for the door which has been once closed, even in the unlocked position of the door lock.

A further object is to provide a door lock mechanism of the above kind, allowing the automotive door to be opened only intentionally and inside as well as outside of the automotive vehicle.

A still other object of the invention to provide the door lock mechanism of the above kind, capable of performing an effective door lock function from inside as well as outside of the automotive vehicle, so as to allow the door opening only by the hands of an authorized person.

A further object of the invention is to provide a door lock mechanism of the above kind, capable of performing an effective unlocking function which means an automatic release of the locked position of the mechanism caused by an unintentional or erroneous locking operation from inside of the vehicle and upon performing of a door closure operation.

It is a still further object of the invention to provide a door lock mechanism, capable of performing a keyless lock operation.

Theseand further objects, features and advantages of the invention will become more apparent when read the following detailed description of a preferred embodiment of the invention by reference to the accompanying drawings illustrative of a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a front view of a preferred embodiment of the door lock mechanism provided with a disk type clutch means.

FIG. 2 is a left-hand side view of the mechanism shown in FIG. 1.

FIG. 3 is a right-hand side view of the same mechanism.

FIG. 4 is a sectional view taken along a section line IV-IV shown in FIG. 2.

FIG. 5 is a sectional view taken along a section line VV shown in FIG. 4.

FIG. 6 is a back side view of the same door lock mechanism and a conventional striker when the former is kept in its unlatched position, thus the door is kept opened although not shown.

FIG. 7 is a similar view to FIG. 6 when the door lock mechanism is kept in its locked position.

In these drawings, same references represent respective same constituent parts throughout all the figrues of the drawings.

Referring now to the accompanying drawings, especially FIG. 1 thereof, the numeral 1 represents a base plate of an automotive door lock mechanism embodying the principles according to this invention, and an open lever 2 substantially shaped into a tee is pivotably mounted at an intermediate point thereof around a pin 3 which is fixedly attached to said base by conventional fixing means such as by riveting as shown at 3a in FIG. 2.

' Open lever 2 comprises a first arm 2a, a second arm 2b and a third arm 2c, and a substantially hook-shaped mechanical connector 5 is pivotably mounted at its one end by means ofa pivot pin 4 on the first arm 20, while the opposite or hooked-end 5a is kept in a link engagement with a pivot pin 10.

The free end of second arm 2b protrudes loosely through a guide opening 1b bored through a side flange la folded towards the viewer from the right-hand side edge of the main body 1 when viewed in FIG. 1, as more clearly be seen in FIG. 3. As will be more fully described hereinafter, said guide opening 1b serves for limiting the range of pivotal movement of the open lever 2 through the engagement of the second arm 2b with the guide opening as above referred to. Although only schematically shown by a small arrow A, the third arm 26 is mechanically connected by a connecting link not shown, with a conventional outside door handle fitted on the automotive door. A vehicle driver or the like authorized person can manipulate the keying mechanism by means of his manual key in the dooropening direction at the will of the person, and then motion will be transmitted through said connecting link to the third arm 20 to the open lever 2 which is then turned counter clockwise, as will be later referred to in a more specific way. Therefore, the third lever 20 can be defined as lock release lever member.

A tension spring 13 is tensioned between a spring mount 2d formed into a small projection made integral with the third lever arm 20, and a spring-receiving opening le formed through said side flange la, thus the open lever 2 being resiliently urged to rotate in the clockwise direction in FIG. 1 around said pivot pin 3.

A locking plate 6 is pivotably mounted on a lower part of the base plate 1 when seen in FIG. 1 and at an intermediate point by means of a pin 8, to which an open plate 7 is fixedly attached at a slightly higher level than the locking plate relative to the plane of the drawing concerning with FIG. 1. One end 6a of the locking plate 6 projects through an open recess 10 formed on the side flange 1a, thus said recess serving as a limiter for the pivotal movement of said locking plate around the pin 8.

In close proximity to the said end 6a, the locking plate 6 is formed with a opening 6b for link connection of the plate through a connecting link, not shown, to an inside locking member, such as a conventional inside push knob, not shown, adapted for keeping thedoor lock mechanism in its locked position by manipulating the knob. In the similar way, a second opening 6c is formed through the locking plate 6 in close proximity to the opposite end thereof, for link connection of the plate 6 through a connecting link, not shown, to an op erating member, again not shown, for being controlled by a manual key. An arm 6d extends substantially upwards in FIG. I, from the plate 6 at an intermediate point between said second opening 6c and the pin 8, said pin is fixedly mounted on this arm 6d.

A further arm 6e extends from the plate 6 upwardly and rightwardly in FIG. 1, at an intermediate point between said opening 6b and the pin 8. A turnover spring 14 is tensioned between an opening 6f bored through said arm 62 and a further opening lfdrilled through the base plate 1. As already hinted, the pin 10 is kept in engagement with the groove formed at the hooked end 5a of the connecting member 5.

-A tension spring 9 is tensioned between an opening 70 drilled through the open plate 7 and a springreceiving projection 1d formed on the base plate 1 at its left-hand edge, for resiliently urging the open plate to turn in the clockwise direction about the pin 8 when seen inFIG. 1.

A stop member lg is formed on the base plate 1 by bending a part thereof up from the plate and a first arm 7b of said open plate 7 is kept normally in pressure engagement with the stop lg under the action of tension spring 9, thereby the extremity of clockwise turning 'movement of the open plate being defined.

With counter clockwise rotation of open lever 2 from the position shown in FIG. 1, thereby connection member 5 being shifted downwards, motion is transmitted therefrom to second arm 70 of said open plate 7 which is therefore turned counter clockwise in FIG. 1 about the pin 8. Third arm 7d of the open plate 7 extends substantially from its center as shown and the extreme outer end 100 of said third arm 7d is bent up from the plane of FIG. 1 towards the viewer so as to engage with the hooked portion 5a of connecting member 5 when the open plate 7 is turned clockwise from the position shown in FIG. 1. This engageable design can be easily seen more clearly by reference to FIG. 2.

As most clearly seen from FIG. 2, inside open lever 11 shaped into a bell crank lever is pivotably mount4d on a substantially triangular projection 101 made integral with said side flange la, by means of a pivot pin 12. The lever 11 is formed with a connection opening 102 which is linkedly connected through a link member, not shown, with a conventional inside door handle, al-

though not shown. A lever arm 11a of said lever 11 has enough length to engage with the second arm 2b of open lever 2. Such engaging position is clearly seen from FIG. 2.

The pin 8 passes loosely through the base plate, and is attached rigidly with a stop means or pawl 15 rotatably received in a first recess 17a which is formed on a mounting member 17 made preferably of a rigid plastic material such as polycarbonate resin. The mounting member 17 is held firmly in position on the base plate 1 by a rigid cover member 16 which is rigidly attached in turn to the base plate by any conventional fixing means such as by riveting as most clearly seen from FIG. 5. One end 8a of the pin 8 is rotatably received in a bearing hole 104 bored through the cover member 16. Thus, pin 8 and pawl 15 are rotatable in unison with each other.

As most clearly be seen from FIGS. 4 and 5, a substantially disk-shaped latch member 18 s rotatably received in a second or circular recess 17b formed on the mounting member 17.

A third or arc-shaped recess 17c is formed in the body of said mounting member 17, said recess 17c being kept in communication with said second recess 17b as most clearly seen from FIG. 5 and receiving a coil spring 20. This spring 20 abuts with its one end against the end wall of said arc-shaped recess 17c and with its other end against a stop pin 19 fixedly attached to the latch member 18, thus the latter being urged resiliently to turn in the counter clockwise direction when seen in FIG. 4. The latch 18 is formed with first, second and a third notches la, 18!; and 180, respectively. As will become more clear as the descrip tion proceeds, the first notch 18a is adapted for receiving a conventional striker 21 which is attached rigidly to an automotive door, not shown, while the second and third notches 18b and 18c. are designed and ar ranged to be engageable with the acting part 15a of said pawl 15. The range of counter clockwise turing motion of the latch 18 when seem in FIG. 4 is limited to a position where the said pawl 15 is brought into engagement with the third notch 18c. Cover-member l6 and mounting member 17 are formed with a recess 16a and an opening 17d, respectively, adapted for receiving the striker 21 when the latter is relatively incoming during coosure of the automotive vehicle door, not shown.

For fixedly attaching the striker 21 to a pillar of the vehicle chassis, not shown, it is formed with a pair of openings and 106 for receiving conventional fixing means such as fixing bolts or similar members.

In the practical use of the door lock mechanism so far shown and described, it is attached fixedly to the vehicle door, although not specifically shown, by means of fixing male screw means, adapted for being received respectively in a plurality of, herein three, conventional screw receiving means 107-110 having corresponding female screw threads adapted for cooperating with said male screw means.

The operation of the aforementioned door lock mechanism is as follows.

When the door is kept in its opened position, the disk latch 18 and the pawl 15 occupy their relative position as shown in FIG. 6.

When the door is being closed, the striker 21 will advance towards the first notch 18a of latch 18. In this course of the movement of the striker, it engages at first with the feeding tooth or projection 18e of latch 18, so as to turn the latter in the counter clockwise direction in FIG. 6, thereby the pawl 15 being turned in the clockwise direction against the action of spring 9. By this relative movement, pawl 15 is shifted frm engagement with third notch to the engaging position with second notch 18b, thence with the feeding tooth 18e of first notch 18a as shown in FIG. 4. The position of the engagement of the pawl with the second notch is called the safety latch position for the door. On the other hand, the position of the engagement of the pawl with the first notch 18a, or more specifically the feeding tooth 18e, is called the perfect latch position by those skilled in the art.

When the driver manipulates the outside open handle, not shown, in the door-opening direciton from the door-closed position, wherein all the working parts of the door lock mechanism are kept in the position shown in FIGS. 1, 2, 3 and 5, motion will be transmitted from the handle to lever arm 26, thereby the latter beng pivotably moved leftwards in FIG. 1, so as to turn the open lever 2 in the counter clockwise direction about the pin 3 so that the connecting member 5 is lowered in FIG. 1 while being kept in sliding contact with pin and the second arm 70 of open plate 7 is urged to shift in a lowered position upon pressure contact with the lowermost extremity of said member 5. Therefore, open plate 7 is rotated together with pin 8 in the counter clockwise direction in FIG. 1, thereby the pawl being rotated in the counter clockwise direction in FIG. 4. In this way, the engagement of the acting part 150 of pawl 15 with the disk latch 18 is released and the latter is urged by the spring action to turn in the counter clockwise direction in FIG. 4, until the entrance part of first notch 18a, the recess 16a of cover plate 16 and the recess 17d of mounting member 17 are brought substantially into registration with each other, as shown in FIG. 6, wherein the striker 21 is brought into separation from disk latch 18 so that the door becomes ready for opening.

On the other hand, when the conventional inside door open handle is manipulated in the door-opening direction when all the working parts of the door lock mechanism are kept in their door-closed position, mo tion will be transmitted from the handle to the arm 11b of inside open lever 11, so as to rotate the latter in the clockwise direction about the pin 12 in FIG. 2, thereby the second arm 2b of open lever 2 being urged by the opposite arm 11a to move upwards in FIGS. 1 and 2, so as to rotate the lever 2 about the pin 3 in the counter clockwise direction. Further operation steps will thus be similar as before, until the door is brought into its ready opening position.

When the authorized person manipulate his manual key, not shown, from outside of the door as conventionally to lock the door for the prevention of unauthorized door opening and for the manipulation of the conventional keying mechanism, again not shown, motion will be transmitted therefrom through a connecting link, not shown, connected linkedly with the left-hand opening 6c, to locking plate 6, so as to turn the latter about the pin 8 in the clockwise direction in FIG. 1. Similar turning effort is given to the locking plate 6 when the person exerts his finger pressure upon the conventional inside locking push knob so as to push down it, since motion will be transmitted therefrom through the connection link, not shown, to the plate 6 for turning the latter about the pin 8 in the clockwise direction in FIG. 1.

In each case, therefore, the pin 10 will perform a circular movement around the pin 8 in the clockwise direction in FIG. 1, thereby the lower or hooked end of connection member 5 being shifted towards right. It wlll thus seen that the working parts of the door lock mechanism are brought in this case into their door lock position, as shown in FIG. 7. In this position, the turnover spring 14 has been brought into its another working position so that it exerts a resilient force upon the locking plate 6 to move in the counter clockwise direction in FIG. 7.

When the person manipulates the outside or inside open handle, as the case may be and under the operating conditions shown in FIG. 7, so as to turn the open lever 2 in the counter clockwise direction from its full line position to its chain line one shown in the drawing, the lowermost end of connection member 5 is not in a position adapted for cooperation with the second arm of open plate 7. Door-opening effort even exerted in this case, therefore, does not provide any influence upon the plate 7 which is therefore unchanged in its position so that the door can not be opened in spite of the door-opening effort. Thus, the door is kept in its locked position.

Now assuming that the person touches the inside locking push knob unintentionally in some or other way from inside of the vehicle so that the knob has been brought into its locking position and the locking plate 6 has been shifted to its position shown in FIG. 7 and that the person manipulate the door in its closing direction, striker 21 and latch 18 are brought into the cooperating position by the closing movement of the door and the latch will be turned as before. In this case, pawl 15 is shifted from engagement with the third notch 18c of latch 18 to the position for pressure engagement with a third tooth 18f formed at an intermediate position between the notches 18b and 18c so that the safety latch position may be brought about, and then when pawl 15 is engaged with a fourth tooth 18e formed between the notches 18a and 18b the full latch position will be realized. During this course and when the pawl 15 is disengaged from third notch 1c and brought into engagement with third tooth 18f, the pawl is turned in the counter clockwise direction in FIG. 4, and accoringly, the open plate 7 is rotated in the counter clock wise direction in FIG. 7.

By this rotation, the third arm 7d of open plate 7 is brought into pressure contact with the hooked part 5a of connection member 5 so that the latter will be swivelled in the clockwise direction in FIG. 7. By this swivelling motion of the member 5, the pin 10 is urged to move leftwards in the drawing, the locking plate 6 being turned thereby in the counter clockwise direction about the axis of pin 8. In this way, the plate 6 is shifted from the position shown in FIG. 6 back to the position shown in FIG. 1. This new position is kept unchanged under the action of turnover spring 14.

After this operation, the door can be brought into its ready-opening position, by manipulating the outside door handle in its opening direction for turning the open lever 2 clockwise about the pin 3 in FIG. 1. Therefore, it will be seen that a kind of the unlocking mechanism has been provided.

For performing the keyless operation so called among those skilled in the art, the person can manipulate the inside locking push knob in such a way that locking plate 6 and connection member 5 are brought into their locking position and then he may manipulate the outside open handle in its door-opening direction and finaly the door is closed.

In this case, open lever 2 and connection member 5 are positioned in the chain line position shown in FIG. 7. During the counter clockwise rotation of open plate 7 while closing the door, the third arm 7d of open plate 7 can not engage with the hooked part 5a of connection member 5 and thus the latter is kept in the position shown in FIG. 7. It will be clear from the foregoing that a door-closing operation can be realized without any use of the conventional door key.

A substantial advantage attainable by use of the disk latch resides in such a feature that the notch means adapted for engagement with the striker can be so designed and arranged that such means occupy a substantially nearer position to the rotational center of the latch, in spite of the no provision ofa rotational center shaft or pin to the latch. If there is an outside force urging the latch to bring it in its disengaging position therefrom, or more specifically, even when a dooropening external and unintentional force is applied, the couple of force induced in the latch is made to be only a minor value and therefore no destructive external force can not be applied to the pawl. In addition, the disk latch is received by its substantially whole peripheral surface so that the possible destructive force capable of being applied to the latch or the mounting member provided therefor may be reduced to a possible minimum in comparison with a substantial large value as met with the conventional fork type orv ratched wheel type which means a substantial progress in the art. Further, in case of the striker kept in its engaging position with the disk latch, the striker is kept in a kind of embraced situation by means of the disengagement prevention tooth 18a for the striker, having a broad and elongated working surface highly effective for the desired purpose and therefore, an outside force occationally acting to a substantial degree in the longitudinal direction of the vehicle chassis and for unintentional separation of the latch disengagement must necessarily encounter a large resistance thereagainst and thus a sudden and unintentional opening of the latched door could not be feared.

It is noted that the pawl 15 is situated in the same position when the door is opened or closed, as shown in FIGS. 4 and 6, and hence the open plate 7 is not moved to be brought into contact with the hooked portion 5a of connection member 5 even in a semi-opened condition of the door, capable of easily bringing the preparatory state of the unlocking and the key-less locking operations. In other words, if the third notch 18a is not formed in the periphery of latch 18 it is very difficult to execute the unlocking-and the key-less operations because of the further leftward displacement of the open plate 7 from its position shown in FIG. 7.

It is further noted that the first notch serves for locking the door by the engagement of the pawl with the first notch and for receiving engageably the striker, while the conventional latch member is provided with separate notches for receiving the striker and for locking the door therewith. Therefore, the inventive latch has larger peripheral surface than that of the conventional one, and hence the force acting in the dooropening direction is advantageously received in the parent inventive mechanism.

According to the novel teaching of the invention, the disk latch having a substantial advantage of providing a considerable degree of strength against the latch destruction as would be met in an emergency is formed with notch means adapted for receiving a pawl means in case of the unlatched condition of the door mechanism and thanks to this main constructional feature, various necessary functions of the door lock mechanism, such as the keeping the door in its closed position in case of closure of the door; the prevention of unintentional door opening or closing from inside or outside of the vehicle; the locking or unlocking operation from inside or outside of the vehicle; and the so-called keyless lock function can be realized in an effective way and with a highly simplified construction of the door lock mechanism.

The embodiments of the invention in which an exclusive property or privilege is claimed are as follows:

1. In a door lock mechanism for an automotive vehicle comprising a wheeled chassis and at least a door pivotably attached thereto, said mechanism comprising in combination,

a striker fixedly attached to said chassis;

a base plate fixedly attached to said door;

a recessed body fixedly attached to said door;

a disc latch rotatably mounted within said recess for movement between a latching and a latch-releasing position;

stop means adapted for engagement with said disc latch to stop it in predetermined positions;

notch means formed on the outer periphery of said disc latch and having a shape for engagingly receiving said striker to move said disc latch to the latching position by closure of said door, said notch means being adapted for engagingly receiving said stop means so as to maintain said disc latch in the latching position and a partially latching position;

latch release operator means pivotably mounted on said base plate for movement between an inoperative position and an operative position;

an intermediate memberadapted to be actuated by said operator means for movement between positions wherein said operator means and said stop means are in coupled and uncoupled relation, and

a locking lever pivotably mounted on said base plate for movement between locked and unlocked posi tions and adapted to move said intermediate member to its coupling or uncoupling positions;

the improvement wherein a further notch means is formed in the outer periphery of said disc latch and serves to maintain said stop means at a certain definite position when the door is opened, and comprising;

disengagable means for actuating said intermediate member to bring said locking lever into its unlocking position when said stop means is disengaged from said further notch means by rotation of said disc latch to its latching position;

said locking lever being moved to its unlocking position under the action of said disengageable means when said disc latch is rotated in a latching direction with said locking lever in its locked position and said operator means in its inoperative position, and

said intermediate member being actuated to effect an idle motion of said disengageable means in response to rotation of said disc latch in its latching direction with said locking lever in its locked position and with said operator means in its operative position;

said first mentioned notch means and said further notch means comprising a first notch adapted for engagingly receiving said striker to rotate said disc latch to its latching position, a second notch engageable with said stop means for maintaining said disc latch in an unlatching position, and a third notch engageable with said stop means for maintaining said disc latch in a partially latching position, and

3. The door lock mechanism as claimed in claim 1 wherein a shaft is rotatably mounted on said body, and said disengageable means and stop means are fixedly attached to said shaft.

UNITED STATES PATENT AND TRADEMARK OFFICE QETEFICATE OF CORRECTION PATENT NO. 3,809,416

DATED May 7, 1974 |NV ENTOR(S) Kenichi Kazoaka It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as strewn below:

In The Heading:

The claimed Priority Data was omitted. Should read:

"'"" January 22, J p n.- 00.0. no

Signed and Scaled this second Day of September 1975 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer (mnnrissr'mu'r ufPaIenIs and Trademarks 

1. In a door lock mechanism for an automotive vehicle comprising a wheeled chassis and at least a door pivotably attached thereto, said mechanism comprising in combination, a striker fixedly attached to said chassis; a base plate fixedly attached to said door; a recessed body fixedly attached to said door; a disc latch rotatably mounted within said recess for movement between a latching and a latch-releasing position; stop means adapted for engagement with said disc latch to stop it in predetermined positions; notch means formed on the outer periphery of said disc latch and having a shape for engagingly receiving said striker to move said disc latch to the latching position by closure of said door, said notch means being adapted for engagingly receiving said stop means so as to maintain said disc latch in the latching position and a partially latching position; latch release operator means pivotably mounted on said base plate for movement between an inoperative position and an operative position; an intermediate member adapted to be actuated by said operator means for movement between positions wherein said operator means and said stop means are in coupled and uncoupled relation, and a locking lever pivotably mounted on said base plate for movement between locked and unlocked positions and adapted to move said intermediate member to its coupling or uncoupling positions; the improvement wherein a further notch means is formed in the outer periphery of said disc latch and serves to maintain said stop means at a certain definite position when the door is opened, and comprising; disengagable means for actuating said intermediate member to bring said locking lever into its unlocking position when said stop means is disengaged from said further notch means by rotation of said disc latch to its latching position; said locking lever being moved to its unlocking position under the action of said disengageable means when said disc latch is rotated in a latching direction with said locking lever in its locked position and said operator means in its inoperative position, and said intermediate member being actuated to effect an idle motion of said disengageable means in response to rotation of said disc latch in its latching direction with said locking lever in its locked position and with said operator means in its operative position; said first mentioned notch means and said further notch mEans comprising a first notch adapted for engagingly receiving said striker to rotate said disc latch to its latching position, a second notch engageable with said stop means for maintaining said disc latch in an unlatching position, and a third notch engageable with said stop means for maintaining said disc latch in a partially latching position, and a fourth notch engageable with said stop means when said disc latch is in the latching position.
 2. The door lock mechanism as claimed in claim 1, wherein said fourth notch is formed at one side of the open end of the first notch.
 3. The door lock mechanism as claimed in claim 1 wherein a shaft is rotatably mounted on said body, and said disengageable means and stop means are fixedly attached to said shaft. 